Changes to commissioning of gas boilers

From April 2013, boiler manufacturers are recommending that gas engineers measure the level of CO in the chimney/flue gases and combustion ratio when a boiler is commissioned. These new requirements have been agreed by the HHIC boiler manufacturers group and will become mandatory by April 2014.

Following installation, the measured CO level and combustion ratio should be recorded on the appropriate commissioning documentation (eg, an HHIC Benchmark Commissioning Checklist), this new requirement will eventually form part of a boiler’s warranty conditions.

These changes have been bought about due to concerns over a very small number of incidents involving newly installed condensing boilers fitted with air/gas ratio valves. Investigations of these incidences showed that high levels of CO were present in the appliances’ combustion products, due to a combination of factors; including inappropriate adjustment of the gas valve and poor flue installation.

The proposal to implement these changes follows-on from last year’s ACS requirements for gas engineers to be competent in using an electronic combustion gas analyser, covered in CPA1.